GLFW: Add support for window occluded notifications on macOS

Based on: https://github.com/glfw/glfw/pull/1123

glfw/cocoa_window.m

@@ -425,6 +425,11 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
     _glfwInputWindowPos(window, x, y);
 }
 
+- (void)windowDidChangeOcclusionState:(NSNotification *)notification
+{
+    _glfwInputWindowOcclusion(window, !([window->ns.object occlusionState] & NSWindowOcclusionStateVisible));
+}
+
 - (void)windowDidMiniaturize:(NSNotification *)notification
 {
     if (window->monitor)
@@ -1671,6 +1676,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return [window->ns.object isKeyWindow];
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return !([window->ns.object occlusionState] & NSWindowOcclusionStateVisible);
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return [window->ns.object isMiniaturized];

glfw/glfw3.h

@@ -828,7 +828,11 @@ extern "C" {
  *  [window attribute](@ref GLFW_FOCUS_ON_SHOW_attrib).
  */
 #define GLFW_FOCUS_ON_SHOW          0x0002000C
-
+/*! @brief Occlusion window attribute
+ *
+ *  Occlusion [window attribute](@ref GLFW_OCCLUDED_attrib).
+ */
+#define GLFW_OCCLUDED               0x0002000D
 /*! @brief Framebuffer bit depth hint.
  *
  *  Framebuffer bit depth [hint](@ref GLFW_RED_BITS).
@@ -1246,6 +1250,24 @@ typedef void (* GLFWwindowrefreshfun)(GLFWwindow*);
  */
 typedef void (* GLFWwindowfocusfun)(GLFWwindow*,int);
 
+/*! @brief The function signature for window occlusion callbacks.
+ *
+ *  This is the function signature for window occlusion callback functions.
+ *
+ *  @param[in] window The window whose occlusion state changed.
+ *  @param[in] occluded `GLFW_TRUE` if the window was occluded, or `GLFW_FALSE`
+ *  if the window is no longer occluded.
+ *
+ *  @sa @ref window_occlusion
+ *  @sa @ref glfwSetWindowOcclusionCallback
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+typedef void (* GLFWwindowocclusionfun)(GLFWwindow*, bool);
+
+
 /*! @brief The function signature for window iconify/restore callbacks.
  *
  *  This is the function signature for window iconify/restore callback
@@ -3583,6 +3605,31 @@ GLFWAPI GLFWwindowrefreshfun glfwSetWindowRefreshCallback(GLFWwindow* window, GL
  */
 GLFWAPI GLFWwindowfocusfun glfwSetWindowFocusCallback(GLFWwindow* window, GLFWwindowfocusfun cbfun);
 
+/*! @brief Sets the occlusion callback for the specified window.
+ *
+ *  This function sets the occlusion callback of the specified window, which is
+ *  called when the window becomes (fully) occluded by other windows or when (a
+ *  part of) the window becomes visible again because an overlapping window is
+ *  moved away.
+ *
+ *  @param[in] window The window whose callback to set.
+ *  @param[in] cbfun The new callback, or `NULL` to remove the currently set
+ *  callback.
+ *  @return The previously set callback, or `NULL` if no callback was set or the
+ *  library had not been [initialized](@ref intro_init).
+ *
+ *  @errors Possible errors include @ref GLFW_NOT_INITIALIZED.
+ *
+ *  @thread_safety This function must only be called from the main thread.
+ *
+ *  @sa @ref window_occlusion
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+GLFWAPI GLFWwindowocclusionfun glfwSetWindowOcclusionCallback(GLFWwindow* window, GLFWwindowocclusionfun cbfun);
+
 /*! @brief Sets the iconify callback for the specified window.
  *
  *  This function sets the iconification callback of the specified window, which

glfw/internal.h

@@ -408,6 +408,7 @@ struct _GLFWwindow
         GLFWwindowclosefun      close;
         GLFWwindowrefreshfun    refresh;
         GLFWwindowfocusfun      focus;
+        GLFWwindowocclusionfun  occlusion;
         GLFWwindowiconifyfun    iconify;
         GLFWwindowmaximizefun   maximize;
         GLFWframebuffersizefun  fbsize;
@@ -670,6 +671,7 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window, _GLFWmonitor* monitor,
                                    int xpos, int ypos, int width, int height,
                                    int refreshRate);
 int _glfwPlatformWindowFocused(_GLFWwindow* window);
+int _glfwPlatformWindowOccluded(_GLFWwindow* window);
 int _glfwPlatformWindowIconified(_GLFWwindow* window);
 int _glfwPlatformWindowVisible(_GLFWwindow* window);
 int _glfwPlatformWindowMaximized(_GLFWwindow* window);
@@ -712,6 +714,7 @@ void _glfwPlatformUnlockMutex(_GLFWmutex* mutex);
 //////////////////////////////////////////////////////////////////////////
 
 void _glfwInputWindowFocus(_GLFWwindow* window, GLFWbool focused);
+void _glfwInputWindowOcclusion(_GLFWwindow* window, GLFWbool occluded);
 void _glfwInputWindowPos(_GLFWwindow* window, int xpos, int ypos);
 void _glfwInputWindowSize(_GLFWwindow* window, int width, int height);
 void _glfwInputFramebufferSize(_GLFWwindow* window, int width, int height);

glfw/null_window.c

@@ -232,6 +232,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return GLFW_FALSE;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return GLFW_FALSE;

glfw/window.c

@@ -88,6 +88,14 @@ _GLFWwindow* _glfwWindowForId(GLFWid id) {
     return NULL;
 }
 
+// Notifies shared code that a window's occlusion state has changed
+//
+void _glfwInputWindowOcclusion(_GLFWwindow* window, GLFWbool occluded)
+{
+    if (window->callbacks.occlusion)
+        window->callbacks.occlusion((GLFWwindow*) window, occluded);
+}
+
 // Notifies shared code that a window has moved
 // The position is specified in content area relative screen coordinates
 //
@@ -867,6 +875,8 @@ GLFWAPI int glfwGetWindowAttrib(GLFWwindow* handle, int attrib)
             return window->focusOnShow;
         case GLFW_TRANSPARENT_FRAMEBUFFER:
             return _glfwPlatformFramebufferTransparent(window);
+        case GLFW_OCCLUDED:
+            return _glfwPlatformWindowOccluded(window);
         case GLFW_RESIZABLE:
             return window->resizable;
         case GLFW_DECORATED:
@@ -1068,6 +1078,17 @@ GLFWAPI GLFWwindowfocusfun glfwSetWindowFocusCallback(GLFWwindow* handle,
     return cbfun;
 }
 
+GLFWAPI GLFWwindowocclusionfun glfwSetWindowOcclusionCallback(GLFWwindow* handle,
+                                                              GLFWwindowocclusionfun cbfun)
+{
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    assert(window != NULL);
+
+    _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
+    _GLFW_SWAP_POINTERS(window->callbacks.occlusion, cbfun);
+    return cbfun;
+}
+
 GLFWAPI GLFWwindowiconifyfun glfwSetWindowIconifyCallback(GLFWwindow* handle,
                                                           GLFWwindowiconifyfun cbfun)
 {

glfw/wl_window.c

@@ -1239,6 +1239,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return _glfw.wl.keyboardFocus == window;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     // wl_shell doesn't have any iconified concept, and xdg-shell doesn’t give

glfw/x11_window.c

@@ -2283,6 +2283,11 @@ int _glfwPlatformWindowFocused(_GLFWwindow* window)
     return window->x11.handle == focused;
 }
 
+int _glfwPlatformWindowOccluded(_GLFWwindow* window)
+{
+    return GLFW_FALSE;
+}
+
 int _glfwPlatformWindowIconified(_GLFWwindow* window)
 {
     return getWindowState(window) == IconicState;

kitty/glfw-wrapper.c

@@ -197,6 +197,9 @@ load_glfw(const char* path) {
     *(void **) (&glfwSetWindowFocusCallback_impl) = dlsym(handle, "glfwSetWindowFocusCallback");
     if (glfwSetWindowFocusCallback_impl == NULL) fail("Failed to load glfw function glfwSetWindowFocusCallback with error: %s", dlerror());
 
+    *(void **) (&glfwSetWindowOcclusionCallback_impl) = dlsym(handle, "glfwSetWindowOcclusionCallback");
+    if (glfwSetWindowOcclusionCallback_impl == NULL) fail("Failed to load glfw function glfwSetWindowOcclusionCallback with error: %s", dlerror());
+
     *(void **) (&glfwSetWindowIconifyCallback_impl) = dlsym(handle, "glfwSetWindowIconifyCallback");
     if (glfwSetWindowIconifyCallback_impl == NULL) fail("Failed to load glfw function glfwSetWindowIconifyCallback with error: %s", dlerror());
 

kitty/glfw-wrapper.h

@@ -585,7 +585,11 @@
  *  [window attribute](@ref GLFW_FOCUS_ON_SHOW_attrib).
  */
 #define GLFW_FOCUS_ON_SHOW          0x0002000C
-
+/*! @brief Occlusion window attribute
+ *
+ *  Occlusion [window attribute](@ref GLFW_OCCLUDED_attrib).
+ */
+#define GLFW_OCCLUDED               0x0002000D
 /*! @brief Framebuffer bit depth hint.
  *
  *  Framebuffer bit depth [hint](@ref GLFW_RED_BITS).
@@ -1003,6 +1007,24 @@ typedef void (* GLFWwindowrefreshfun)(GLFWwindow*);
  */
 typedef void (* GLFWwindowfocusfun)(GLFWwindow*,int);
 
+/*! @brief The function signature for window occlusion callbacks.
+ *
+ *  This is the function signature for window occlusion callback functions.
+ *
+ *  @param[in] window The window whose occlusion state changed.
+ *  @param[in] occluded `GLFW_TRUE` if the window was occluded, or `GLFW_FALSE`
+ *  if the window is no longer occluded.
+ *
+ *  @sa @ref window_occlusion
+ *  @sa @ref glfwSetWindowOcclusionCallback
+ *
+ *  @since Added in version 3.3.
+ *
+ *  @ingroup window
+ */
+typedef void (* GLFWwindowocclusionfun)(GLFWwindow*, bool);
+
+
 /*! @brief The function signature for window iconify/restore callbacks.
  *
  *  This is the function signature for window iconify/restore callback
@@ -1641,6 +1663,10 @@ typedef GLFWwindowfocusfun (*glfwSetWindowFocusCallback_func)(GLFWwindow*, GLFWw
 glfwSetWindowFocusCallback_func glfwSetWindowFocusCallback_impl;
 #define glfwSetWindowFocusCallback glfwSetWindowFocusCallback_impl
 
+typedef GLFWwindowocclusionfun (*glfwSetWindowOcclusionCallback_func)(GLFWwindow*, GLFWwindowocclusionfun);
+glfwSetWindowOcclusionCallback_func glfwSetWindowOcclusionCallback_impl;
+#define glfwSetWindowOcclusionCallback glfwSetWindowOcclusionCallback_impl
+
 typedef GLFWwindowiconifyfun (*glfwSetWindowIconifyCallback_func)(GLFWwindow*, GLFWwindowiconifyfun);
 glfwSetWindowIconifyCallback_func glfwSetWindowIconifyCallback_impl;
 #define glfwSetWindowIconifyCallback glfwSetWindowIconifyCallback_impl